GIMP is a digital photo manipulation tool for Windows (and many other platforms) that’s considered to be the open source (free) answer to Adobe Photoshop. Like Photoshop, GIMP is suitable for a variety of image manipulation tasks, including photo retouching, image composition, image construction, and has many other capabilities. It can be used as a simple paint program, an expert quality photo retouching program, an online batch processing system, a mass production image renderer, an image format converter, and so much more.

GIMP is amazingly expandable and extensible – it is designed to be augmented with plug-ins and extensions to do just about anything. The advanced scripting interface allows everything from the simplest task to the most complex image manipulation procedures to be easily scripted.

One of GIMP's strengths is its free availability from many sources for many operating systems. So, if you don’t want to pay the price for Photoshop, GIMP is definitely the app for you!

GIMP features:

Full suite of painting tools including Brush, Pencil, Airbrush, Clone, and more – including the support of custom brushes & patterns

Extremely powerful gradient editor and blend tool

Transformation tools including rotate, scale, shear, flip, and more

Supports a variety of selection tools such as rectangle, rounded rectangle, ellipse, free, fuzzy, and more